Wanted: new mascot for 137-year-old racing event. Must appeal to the young and Web-savvy. Social media experience required.

That's the premise of an anonymous marketing campaign unveiled this month to unseat the tweeting centaur Kegasus as the mascot of the Preakness Stakes infield party. The new candidates? A leprechaun and the Easter Bunny.

The marketing firm hired by the Maryland Jockey Club is presumably behind the campaign, coming as it does as the Preakness advertising season starts to get under way. But it's not taking credit.

"We've got nothing to do with this," said Jimmy Learned, president of Elevation Ltd., which is handling marketing for the Preakness for the third year.

Stealth campaigns like this one are increasingly commonplace as marketers seek to create viral buzz without leaving traces of their well-funded creators. The idea is that people respond better to a pitch when they don't know they're being marketed to. But marketing experts say that denying ownership of a marketing gimmick could seriously backfire when the real authors are revealed. People, it seems, don't like to be fooled.

The premise of the new campaign, which was unveiled Monday with a tongue-in-cheek news release, is that Kegasus has disappeared, and an "International Brotherhood of Mythical Creatures" is lobbying for a creature to take the centaur's place. Each character has its own Facebook profile and lobbying video.

The release has no authors or credits, and the listed phone number is to a fake voice mail.

Jockey Club President Tom Chuckas said the Preakness advertising campaign hasn't been finalized. But the anonymous campaign fits in with the bold marketing approach organizers have taken in the past three years to lure young people back to Pimlico after a disastrous 2009.

There are some clues connecting this campaign to Elevation. It comes close on the heels of the announcement of Preakness' musical headliners; the promotional videos are professionally made, and look similar to those from last year's Kegasus campaign; and a hard-to-find image on the campaign's Facebook page links to Elevation.

Learned was coy when asked about the campaign's authorship. When presented with the Facebook link to Elevation, Learned said someone had hacked the firm's website. "You never know what these mythical creatures are capable of," he said.

Companies responsible for stealth campaigns never own up to them, and that's the point.

"When consumers realize they're being marketed to, they put up barriers," said Rebecca Hamilton, a marketing professor at the University of Maryland. "People are more likely to respond to advertising if it's like someone telling them a conversation."

In the past five years, thanks to the explosion of marketing channels online, anonymous campaigns have become widely used in the ad industry despite concerns about their methods, marketing experts say.

On television, such campaigns are mostly forbidden by the Federal Communications Commission, which requires marketers to note when testimonials are by actors, for instance. But with the advent of social media, Facebook, Twitter and You Tube have become a Wild West of so-called black-hat marketing practices.

On Facebook, especially, where users can create exaggerated or even fictional profiles with no one catching on, marketers have free rein.

"When you get into digital media, you live in this world where you feel you can be anonymous and you can get away with things," said Chris Harris, a professor at Johns Hopkins University's Carey Business School who specializes in digital marketing. "It's pretty widespread, in that a lot of marketers, in house as well as big marketing agencies, think they can try to pull something off. Because of all the new technology marketing channels available, there's a desire to want to go viral."

In 2002, mobile-phone manaufacturer Sony Ericsson hired actors in several cities to go up to people on the street and ask them to take a picture with the company's brand-new camera-phone. In 2006, the viral marketing firm Zipatoni started a fake blog to promote the new PlayStation Portable game console. Hamilton points to the company Bzzagent, which has paid its employees to give positive reviews of its clients' products on shopping sites like Amazon.

Perhaps best-known was "Lonelygirl15," a series of YouTube confessionals seen by millions. The titular character turned out to be an actress, and the people who videotaped her and placed the videos on YouTube were filmmakers who had been signed to Creative Artists Agency, a major talent agency.

While it's hard to estimate exactly how prevalent such practices are — a successful stealth campaign remains secret — marketers spend 15 percent of their budget on word-of-mouth, buzz and viral campaigns, according to a 2008 study in the Journal of Public Policy & Marketing. Advertising Age estimated in 2006 that $100 million to $150 million a year is spent on this sort of marketing.

Though Learned said the latest campaign is not coming from Elevation, he added that stealth campaigns can be an effective way to harness the power of social media and stoke excitement among the prized "millennial" demographic.

"History has shown some are great," he said. "That's the beauty of the evolving media of communications. Depending on what your objectives are, stealth campaigns are inspired and intuitive. As communicators, you have to be open to a myriad opportunities."

Provocative advertising and music appealing to young people have become increasingly important ways for the Jockey Club to sell tickets to the Preakness, which has seen a drop in attendance since setting a record in 2008.

Chuckas credits the provocative "Get Your Preak On" and Kegasus campaigns with bringing excitement and higher attendance to the events in the past two years — more than 107,000 people attended last year, up from the year before, and markedly up from the low of 78,000 in 2009, the year the Jockey Club started barring infield attendees from bringing their own alcohol.

Beyond bold marketing, organizers have already signaled they want to court attention this year by selecting headliner Wiz Khalifa, who has a penchant for rapping about marijuana.

Washington-based Elevation, which has been in charge of the Preakness' marketing for the last three years, has pursued the racing event's traditional audience with advertising highlighting the Preakness' storied history and has launched racier campaigns — "Get Your Preak On," Kegasus — aimed at young people that have offended more conservative racing fans.

Learned defended the approach, saying his firm has been able to slowly chip away at the infield's reputation as the site of drunken debauchery.

"We don't apologize for anything," he said. "I have great pride in Kegasus. ... Tom Chuckas understands that what the sport itself needs is an infusion of young blood."

Still, marketing experts says stealth campaigns cross ethical lines. They suggest owning up to a campaign because the risks of not doing so outnumber the benefits.

"While you may think you're pulling one over on everybody, there is just as a great a risk that it'll do damage and people will take great pride in exposing you," said Hopkins' Harris.

When consumers discovered that the PlayStation Portable blog created by Zipatoni was a fake, they reacted angrily.

"Consumers know that marketing agents are trying to persuade them, but they want to know where it's coming from," UM's Hamilton said.

For legacy brands like the Preakness Stakes, the risk is doubled because people associate them with tradition and expect sincerity, some advertising experts say.

More effective viral campaigns are upfront about their sponsorship — like the Old Spice commercials — and succeed because of their creativity, Harris said. Or they have an interactive component, such as a coupon that might be passed on. When a campaign starts out on a false premise, it risks becoming associated with deceit.

"In general, people catch on, and they'll say, 'They're not being honest with me,'" Harris said. "We've all become so cynical. There's so much misinformation out there, people have a very bitter reaction to feeling like they're being scammed."

Learned said he is still hard at work on a campaign for the Preakness and will present it to the Jockey Club in two weeks. The official unveiling is set for later in March.

Asked if he was concerned about a controversy similar to the Zipatoni blog, he said he wasn't worried.

"The risk is not creating controversy but creating vanilla work," he said.